Electrical submersible pumps (ESP) are commonly used in hydrocarbon producing wells. An ESP includes a pump driven by an electrical motor. Dielectric lubricant in the motor lubricates motor bearings. A pressure equalizer or seal section has an elastomeric bladder or a metal bellows with an interior in fluid communication the motor lubricant to reduce a pressure differential between the motor lubricant and the wellbore fluid exterior of the motor. Usually, the seal section connects between the motor and the pump.
The elastomeric bag has open upper and lower ends. A guide tube extends through the open ends and secures to retainers on the upper and lower ends of the seal section. A drive shaft sealed at the upper retainer from well fluid locates within the guide tube. The seal is usually a mechanical face seal, which allows slight leakage of well fluid into the upper retainer. A well fluid port in the upper retainer admits well fluid into the housing exterior of the bladder to exert a pressure force against motor lubricant in the interior of the bladder. It is important to minimize well fluid leakage into the interior of the bladder because it could migrate down to the motor.
There are a number of designs used and known to secure the upper and lower ends to the upper and lower retainers. In one past technique, the open ends of the bladder were adhesively bonded to the upper and lower retainers. ESPs must be retrieved periodically for maintenance. Reconditioning a seal section usually involves replacing the bladder. If adhesively bonded, it was difficult to remove them from the retainers, normally requiring at least part of an expensive retainer to be thrown away.